January 21, 2020

Solar Project: Finishing Up Odds and Ends

Last week we had lovely weather and a break from the rain. We took advantage of it to put some finishing touches on our solar project.

First was to add an exhaust fan to the battery box to vent heat and hydrogen gas (a by-product of the batteries when they charge). A lot of people seem to like the Zephyr Power Vent, which can be installed as part of a vent pipe. It uses 3 watts of power and moves air at 6 CFM. It would be handy if one was venting from a basement, say, to the outside, but our battery box is already outside. Plus, it's pricey, about $110.

Instead, we got a DC cooling fan which Dan installed in the back side of the battery box. It uses 2.1 watts and pushes air at 43.6 CFM. It was $12.



The fan connects to the charge controller, which will regulate it.

Dan's roof design for the box allows air in under the roof eaves, but he also added air intake holes on both ends of the box.


To monitor temperature inside the box, we added a Remote Temperature Sensor.


This also connects to the charge controller and enables the controller to optimize battery charging according to temperature. It was about $30 and seemed a good investment for better battery management.

Another task was to check the specific gravity of the battery cells with a hydrometer. The battery manual gives details on the specific gravity. Battery cells were topped off with distilled water if needed.


Lastly, the batteries were connected. You may recall that they are 6-volt, 235 amp-hour golf cart batteries.


I showed you a diagram in my Solar Pantry Project: Batteries post and explained that by wiring pairs of batteries negative to positive (series connection) and then wiring the pairs together with all positive on the one side and all negative on the other (parallel connection), we now have a 12-volt, 705 amp-hour battery bank. Another task completed.

We're getting close to power day!

14 comments:

Boud said...

I can't wait to see you throw the switch or cut the ribbon or whatever the ceremony will be! There will be loud cheers from this follower.

Sam I Am...... said...

You guys are amazing and so knowledgable!

Leigh said...

Boud, it's been slow going (or so it's seemed) but we're finally almost there!

Sam, well, it's been a learn as we go process. More monkey-see-monkey-do than expert. :)

Ed said...

I learned about hydrogen gas and batteries in my early teens. A fellow who spent the night at our family's house went to jump start his dead van battery one cold morning and the spark ignited the hydrogen gas and caused the whole thing to explode literally in his face. Fortunately he wasn't seriously hurt other than a few acid burns to his hand and I was shielded by the angle of the open hood. Since that time, no matter how free of hydrogen gas a battery might be with modern sealed batteries, when I go to hook up cables to the battery, I always look away for that last connection to save my eyes should it explode.

Cockeyed Jo said...

Wtg on the cheaper venting solution. :o) I was going to suggest it but, as a suggestion I offer, buy several of these fans. They are mass produced in China. Even under the eave it is still subjected to extreme heat and cold. The blades are only plastic. The remote sensor is an excellent idea. I hadn't thought of that although we are planning a much bigger system with a battery building.

greenjournalhomestead said...

Really enjoying the battery bank photos. Will be doing something similar soon. Very entertaining / helpful as always. Thanks!

Nancy @ Little Homestead In Boise said...

Great job!!!

Leigh said...

Wow, Ed. It's very fortunate it wasn't worse. What a way to learn! A lesson you won't forget and probably neither will those of us who read your comment.

I use sealed batteries inside, for smaller things like my fan, battery charger, and back porch light. Unfortunately, they are more expensive than lead acid batteries and with shorter lifespans. Both of those things were key in our final decision.

Jo, that's probably a good idea. Anything extra for backup can't hurt. I wonder what the Zephyr fan fan blades are made of. I couldn't find where it said.

You can likely find a temp sensor for whatever brand of charge controller you choose. Seems like a handy addition.

Greenjournalhomestead, thanks! I know you must be very excited about your own project. Feels like a step in the right direction, doesn't it?

Nancy, thanks!

Hill Top Post said...

How exciting that all the hard work will soon be paying off! I will be watching for coverage of the big day which I am sure you will share with all of us here.

Toirdhealbheach Beucail said...

Looks so impressive. So excited for power day!

Leigh said...

Mary, thanks! It's amazing to look back and realize how much we've learned. It will be a relief to know our food storage won't be affected by power outages.

TB, the next step is to move the freezer! That will be an all day job with having to defrost it first. Hopefully, in the next couple of days.

Rain said...

Power day will be so rewarding! I love the fan installation, thanks again for the detailed post!! :)

Mama Pea said...

Slow and steady wins the race. Some of these things just can't be rushed. Or if we do rush them, we end up paying the price in some way. You and Dan are so good at researching all the ins and outs before proceeding. Lookin' good!

Leigh said...

Rain, we're almost there!

Mama Pea, I agree. But I'll feel better about making the switch knowing we've attended details. I'm sure we'll still have a lot to learn, but hopefully we've made a good start.